Composite bushing



Patented Oct. 14, 1947 UNITED ,s'rATE COMPOSITE RUSHING Thomas L. Eawick, Akron, OllioV Application January 24, 1945, serial No. 514,430

3 Claims.

e i 1 This invention relates to composite bushings comprising rubberor rubber-like material, such f as are used, for example, in spring-shackles fory automobiles, to connect two members having relative angular movement about the axis of the bushing, such movement being permitted by deformation of the rubber or the likerwithoutsurface friction.

Another example is the use of a bushing comprising a layer of rubber or the like to provide a cushioning seat for a bearing.

H'eretofore the use of such bushings in places where they come in contact with oil or grease has My chief objects are to overcome these dirn-A culties, and, morespecifically, to provide a bushing adaptedto have along life of strong resilience even though it be used in the presence of oil, grease or other.substance that is harmful to natural rubber. Further objects are simplicity and economy of manufacture and ease of application.

Of the accompanying drawings, y

Fig. 1 is an axial section of a composite bushing embodying my invention in its preferred form.

Fig. 2 is a similar-section showing an alterna.-` tive type of assembly.

Referring to the drawing, I attain the above stated` objects, in a convenient and economical manner, by providing, preferably as' a vpreassembled unit, a composite bushing comprising an inner metal member I0, which can be annular, as shown, but fis not necessarily so; any outer metal shell member II; between the two, but of less length, a layer of natural rubber I2; and, at

-or near each end of the rubber member I2, a sealy ing ring I3 embraced between, and preferably set in shallow grooves formed in, the two metal members, as shown in Fig. 1. l

The sealing rings I3 preferably are of Neoprene oi; other oil-resistantsynthetic rubber, but can bek of other protective material. Preferably they are yspaced a little away from the respective ends of the naturalrubber layer, as shown, so that its deformation does not exert any thrust upon them and'so that oil is not drawn to it immediately or in largeV quantity by capillary attraction in case the sealing ringv eventually loses some of vits tightness of tit by reason of cold flow.

Each of the'sealing rings I3 is made of such cross-sectional size as to be under substantial radial compression when in place. The grooves, preferably, are arcuate in cross-section and the ring circular in cross-section, for ease of assembly and for continued snugness of t throughout the contacting surfaces in spite of lessening of radial compression by cold flow. l

Preferably the natural rubber member I2 is put under high radial compression by first vulcanizing it to the inner metal member and then reducing its radial dimension by forcing them both into the outer metal member II, in a manner Well I known in the art, after which the sealing rings are forced in between the two metalmembers, and into the grooves of the latter, from the respective ends of the assembly. This can be facilivtated by beveling one or more of the annular metal corners, as at I4. Also, the sealing rings can be coated with an adhesive adapted to serve. as a lubricant as the rings are forced intoplace between the metal members.

The adhesive is thenV permitted to set and thus' A vwholly cylindrical in their portions which embrace the oil-excluding rings, I3a, I3a.

Various other modificaitons are possible within the scope of the invention as defined by the appended claims.

I claim:

1. The combination of an inner rigid member formed with a generally cylindrical outer face,

'an outer rigid member surroundingsaid inner member and formed rwith a generally cylindrical inner face which with the said outer face of the inner member defines an annular space, a natural-rubber bushing so mounted rin said space as to resist relative movement of said members but at each end terminating short of the adjacent end of said space and, in said space, beyond each end of the naturalrubber bushing, and between generally cylindrical portions of said faces, a ring ol oil-resistant synthetic material having 3 substantially the resilient deformability of vulcanized soft-rubber, the ring being held under radial compression wholly bythe said faces.

2. The combination of inner and outer rigid members defining an annular space between them and, mounted in said space radially between said rigid members, a natural-rubber bush- 4 which at least one of the rings of oil-resistant material is seated in an, annular groove formed in one of the two dened rigid members.

THOMAS L. FAWICK.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,282,239 Opsahl May 5, 1942 83,899 Allison Nov. 10, 1868 837,482 Libert Dec. 4, 1906 15 1,942,489 Pfeierle Jan. 9, 1934 2,294,452 Guy Sept. 1, 1942 1,958,119 Tarr 1-- May 8, 1934 

